Effects of Li and aspirin co-administration on hypothalamic levels of IL-6 and TNF-α. Rats were fed regular food (control) or Li-containing food (0.1%) for 42 days. Low-dose aspirin (1 mg/kg, ip) was given alone or together with Li. On days 21 (a,c) and 42 (b,d) of the treatment protocol, 2 h before sacrifice, LPS (1 mg/kg) was administered as described under Materials and Methods. Determination of IL-6 and TNF-α was done using specific ELISA kits. Results are means ± SEM of a single representative experiment out of two demonstrating a similar pattern, with eight rats/group. (a) HT IL-6 levels on day 21: One-way ANOVA, F = 5.847, p < 0.0001. Post-hoc Fisher’s LSD test: Control vs. Li, Li + ASA, LPS + Li, LPS + ASA and LPS + Li + ASA, NS; Control vs. ASA, p = 0.015; Control vs. LPS, p = 0.025; LPS vs. LPS + Li, LPS + ASA, NS; LPS vs. LPS + Li + ASA, p = 0.004; LPS + Li vs. LPS + ASA, NS; LPS + Li vs. LPS + Li + ASA, p = 0.015; LPS + ASA vs. LPS + Li + ASA, p = 0.02. (b) HT IL-6 levels on day 42: One-way ANOVA, F = 5.566, p < 0.0001. Post-hoc Fisher’s LSD test: Control vs. ASA and Li + ASA, p < 0.0025; Control vs. Li, LPS, LPS + Li, LPS + ASA and LPS + Li + ASA, NS; LPS vs. LPS + Li, LPS + ASA, LPS + Li + ASA, NS; LPS + Li vs. LPS + ASA and LPS + Li + ASA, NS; LPS + ASA vs. LPS + Li + ASA, NS. (c) HT TNF-α levels on day 21: One-way ANOVA, F = 2, 714, p = 0.017. Post-hoc Fisher’s LSD test: Control vs. Li + ASA, LPS + Li, LPS + ASA and LPS + Li + ASA, NS; Control vs. LPS, p = 0.047; LPS vs. LPS + Li and LPS + ASA, NS; LPS vs. LPS + Li + ASA, p = 0.022; LPS + Li vs. LPS + ASA and LPS + Li + ASA, NS; LPS + ASA vs. LPS + Li + ASA, NS. (d) HT TNF-α on day 42: One-way ANOVA, F = 8.325, p < 0.0001. Post-hoc Fisher’s LSD test: Control vs. Li + ASA, LPS + ASA and LPS + Li + ASA, NS; Control vs. LPS and LPS + Li, p < 0.0058; LPS vs. LPS + Li, LPS + ASA, NS; LPS vs. LPS + Li + ASA, p = 0.0002, LPS + Li vs. LPS + ASA and LPS + Li + ASA, p ≤ 0.001; LPS + ASA vs. LPS + Li + ASA, p = 0.037. Asterisks and symbols denote the following: * p < 0.05 vs. Control, # p < 0.05 vs. LPS; ^ p < 0.05 vs. LPS + Li, § p < 0.05 vs. LPS + ASA. Abbreviations: ASA—acetylsalicylic acid, Li—lithium, LPS—lipopolysaccharide, NS—nonsignificant.